It has previously been proposed--see the referenced U.S. Pat. Nos. 3,745,995 and 3,820,534--to provide an inductive receiving coil, preferably having a ferromagnetic core, for association with osteosynthesis implantates. The receiving coil has two or more connecting terminals, connected to electrodes which are attached to an injured or damaged bone which is fixed in relative position by the osteosynthesis implantate. Such an implantate may, for example, be a bone nail, securing together the ends of a fractured bone by extending through the marrow duct. After the operation of introducing the bone nail, and of closing the wound, a low-frequency electrical current is induced in the coil which flows through the electrodes and the damaged bone region, and promotes healing and reformation of bone substance.
Such osteosynthesis implantates are known as electro-osteosynthesis implantates and are provided with the receiving coil and the electrode connections, as delivered from the manufacturer. The manufacture of any one electro-osteosynthesis implantate requires individual, special manufacture in which the electrical winding elements and the osteosynthesis implantate are individually associated. Such implantates may, also, be in the form of flat or bendable plates. The winding section is individually and securely connected to the implantate by adhesion, clamping connection or welding; likewise, the electrodes or electrode connection are so adhered or connected. Surgical clinics, trauma stations in hospitals, and the like, require a large stock of different types of electro-osteosynthesis implantates, for example bone nails of many different lengths in many different diameters. Such electro-osteosynthesis implantates are expensive and stocking and storage of a large number of such items in many different sizes, the requirements for which are hardly predictable, is a substantial drain on limited financial resources of public and private health facilities. Frequently, therefore, the patient is subjected to multiple surgical procedures since electro-osteosynthesis implantates were frequently introduced into the patients only in a second operation, after the initial operation of fixation of the bone has taken place, the type and size of the required electro-synthesis implantate has been determined and the appropriate unit has been ordered and received from the manufacturer.
Developments in surgical devices have been undertaken to reduce the financial load on health facilities and to reduce the requirement for stocking of specific electro-implantates. U.S. Pat. No. 3,820,534 describes a belt-like element which is furnished with electrodes and a connecting element on which a coil is secured. After implantation of a bone nail, for example, the belt-like element is placed around the bone, and the connecting coil can be connected to the bone nail with one terminal. It has also been proposed to provide a loose pick-up coil which is embedded in a biologically tissue-compatible plastic material and which can be connected to bone screws by means of snap-button type connections. The bone screws function as electrodes across which an electric current will flow (see German Disclosure Document DE-OS No. 23 11 817). U.S. Pat. No. 3,918,440 describes such a loose receiving coil in combination with bone screws, in which the head of the bone screws is insulated so that it can be used for attachment of a bone plate. The screws, themselves, form the electrodes which are insulated with respect to the bone plate.
The loosely implanted pick-up coil, as well as the belt-like element, and the snap button or push-button type connections are an entirely satisfactoy substitute for premanufactured electro-osteosynthesis implantates. Use of the belt-like element introduces additional complexity; the loose pick-up coil is difficult to secure.